Chlorodifluoromethane is a type of chlorofluorocarbon (HCFC), and is also known by other names, such as R22 and HCFC22 (herein sometimes referred to as “R22”). Although R22 has been widely used as a refrigerant, it has recently been pointed out that R22 may cause ozone layer depletion and global warming.
Accordingly, in advanced nations, alternative refrigerants have been developed. As a typical alternative refrigerant, R410, which is a mixed refrigerant of HFC32 and HFC125, has been widely used. On the other hand, in developing countries, the replacement of R22 is about to begin under the Montreal Protocol. Since not depleting the ozone layer (having a zero ozone depletion potential) is a condition required of alternative refrigerants, R410A is one of the alternative refrigerant candidates.
On the other hand, in advanced nations, to reduce the global warming impact, a refrigerant having a low GWP (global warming potential) has been desired. Also, in developing countries, from the viewpoint of preventing global warming, a refrigerant having a low GWP is considered preferable, rather than R410A, which has a global warming potential higher than R22.